Physical Sciences Division Research Highlights

Gases Drawn Into Smog Particles Stay There

SPLAT helps pinpoint pollution particles to improve smog predictions

SPLAT II provides measurements of particles with unprecedented sensitivity and precision to scientists such as Alla Zelenyuk. Enlarge Image

Airborne gases settle in smog particles from which they cannot escape, according to research published February 21 in the Proceedings of the National Academy of Sciences. The results could explain why pollution computer models underestimate organic aerosols—the major component of smog particles and the least understood component in climate change calculations.

The study, led by University of California, Irvine air chemist Barbara Finlayson-Pitts, combined alpha-pinene, a common ingredient in household cleaners such as Pine Sol and outdoor emissions, with oxides of nitrogen and ozone to mimic smog buildup. Atmospheric chemist Alla Zelenyuk at Pacific Northwest National Laboratory evaluated millions of the artificial smog particles one-by-one using a one-of-a-kind, 900-pound instrument known as SPLAT (a single particle laser ablation time-of-flight mass spectrometer).

"Being able to study individual particles gives us so much detail about how pollution evolves," said Zelenyuk. "Incorporating what we found about these particles into computer models will help in modeling pollution and climate as well."